Dew formation prediction method and apparatus, environment air temperature estimating method and apparatus and recording and/or reproducing apparatus

1. Field of the Invention A dew formation occurrence detection apparatus for detecting the dew formation on a drum of a tape transport system provided on the electronic equipment as an object for measurement. The dew formation occurrence detection apparatus includes a drum temperature detection unit for detecting the temperature of the drum , an environment air temperature acquisition unit for acquiring the environment air temperature of the electrical equipment and a dew point temperature calculating unit for calculating, from this environment air temperature, the dew point temperature at the humidity which takes the operating environment of the electronic equipment into account. When the temperature of the drum is not higher than this dew point temperature, it is verified that dew formation has occurred.